In general, representative animals which are reared and managed as livestock include cattle, swine, horses, etc., and the growth processes and physical conditions of such livestock are susceptible to changes in rearing environments or the like, so the animals require sufficient attention in rearing and management. For example, horses are known to have tendencies to develop physical symptoms such as diarrhea induced by various types of stress due to changes in rearing environment such as feed. In the intestines of horses (in particular, foals), there are fewer bacteria compared to other livestock, and the bacteria suffer extreme decreases due to changes in rearing environment. Therefore, intestinal flora which create the ecosystem of intestinal bacteria are damaged, and the ecosystem is disturbed, resulting in occurrence of symptoms such as diarrhea. Such symptoms have an adverse effect on physiological functions such as decrease in digestion and absorption ability, inhibition of growth, and suppression of immune system, so it causes great damage to the race horse production field.
In recent years, feeds containing bacteria such as lactic bacteria and bifidobacteria have been widely used in rearing and management of horses (see, for example, Patent Documents 1 to 4). Those feeds may ameliorate intestinal flora and provide physiological effects such as growth promotion and diarrhea amelioration by adhesion of the bacteria in the feed to the intestines of horses.
However, even if those feeds are used, the administered bacteria do not adhere to and proliferate in the intestines of horses, and the effects of ameliorating physiological symptoms such as diarrhea are not sufficiently exerted in many cases. Therefore, in actuality, various antibiotics are now administered depending on the symptoms.
Although antibiotics to be administered may effectively ameliorate physical symptoms of horses, they may have effects such as killing bacteria present in the intestines of horses and cause side effects such as aggravation of diarrhea symptoms in many cases. Meanwhile, such antibiotics kill not only bacteria present in the intestines of horses but also useful bacteria that are separately administered as feed or the like, so even in the case where a feed containing useful bacteria as living bacteria is administered to horses, effects of the administered bacteria cannot be sufficiently achieved, and effects of ameliorating physical symptoms that cause digestive disorders such as diarrhea are low.
Therefore, for a feed containing bacteria to be used in the rearing and management of horses, it is necessary not only to select bacteria such as lactic bacteria and bifidobacteria that have the effect of ameliorating intestinal environments but also to select bacteria that exhibit specific adhesion to the digestive epithelia of a horse and proliferative activity and have excellent effects of improving intestinal environments of horses and to select bacteria that have excellent resistance to various antibiotics that may be administered as needed depending on the physical symptoms of horses.
Patent Document 1: Japanese Patent Laid-open No. 59-46208
Patent Document 2: Japanese Examined Patent application publication No. 3220699
Patent Document 3: Japanese Patent Laid-open No. 2001-519144
Patent Document 4: Japanese Patent Laid-open No. 2002-58432